The present invention relates to surgical instruments, and particularly to surgical instruments used in minimally invasive endoscopic transitional space surgeries or other endoscopic procedures. More particularly, the present invention relates to a surgical instrument used for cutting tissue.
During most minimally invasive surgeries of the sinuses, knee, shoulder, and other joints, a smaller surgical instrument is preferred. A number of instruments have been developed, including those shown in U.S. Pat. Nos. 5,443,475 and 4,977,900, for such surgeries. The disclosure of these patents is incorporated herein by reference for purposes of combining techniques and concepts. Instruments such as those shown in these referenced patents are typically used with an endoscope which allows the surgeon to view the interior of the area under repair through an eye piece or, alternatively, on a video display screen.
An initial process in many minimally invasive endoscopic transitional space (sinus) surgeries is cutting the uncinate process. The uncinate process is an obstructive piece of cartilage and is cut for the purpose of exposing the ostium, which leads into the maxillary sinus cavity. A large degree of precision, maneuverability, and control is needed in order to effectively cut the uncinate process and many other tissues in endoscopic surgeries.
According to the present invention, a surgical instrument is provided for cutting tissue. The instrument includes a shaft having distal and proximal ends and a cutter coupled to the distal end of the shaft. The cutter is formed to include a base, a slider positioned to lie adjacent to the base, and a tip coupled to the base and the slider. The base is formed to include an aperture providing two cutting edges and the tip is also formed to include two corresponding cutting edges for cooperation with the cutting edges of the base. The cutter is formed to move between a filly open position in which the cutting edges of the tip form an obtuse angle relative to the shaft to a fully closed position in which the tip is received within the aperture of the base. The instrument is also formed to include a handle coupled to the proximal end of the shaft. The handle is arranged to move the cutter between open and closed positions.
In preferred embodiments, the handle is formed to include a right handle grip, a left handle grip, and a center beam positioned to lie between the right and left handle grips. The right and left handle grips are coupled to the center beam at a proximal end of the handle and are normally spaced-apart from the center beam at a distal end of the handle. In order to move the cutter to the fully closed position, the handle grips are squeezed toward the center beam in a direction transverse to an axis running through the shaft. The surgical instrument of the present invention is adapted to be held by the thumb and index finger, supported on the middle finger and actuated by squeezing the thumb and index finger together.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.